When using a relative URL for the xsltUrl attribute, e.g.
test.jsp:
	<x:transform xsltUrl="test.xsl">SOME CONTENT</x:transform>

even if there exists a test.xsl in the same deploy directory
as test.jsp, the following error results:

javax.servlet.jsp.JspTagException:
javax.xml.transform.TransformerConfigurationException:
javax.xml.transform.TransformerConfigurationException:
javax.xml.transform.TransformerException: java.io.FileNotFoundException:

What is particularly interesting is the file that it's looking for:
It seems to prepend my _development_ directory to the path.

E.g. I use the standard Tomcat 4.0 recommended development directory format:
<DEVEL>/test-jstl/web/test.[jsp|xsl]
and deploy to tomcat's webapps directory:
<TOMCAT>/webapps/test-jstl/test.[jsp|xsl]

Then the actual error which results when I try loading test.jsp is:
	java.io.FileNotFoundException: <DEVEL>/test-jstl/test.xsl

If I modify test.jsp to contain:
	<x:transform xsltUrl="web/test.xsl">

Then it actually finds the file, and works mod the following error.
For some reason if test.xsl contains the standard header:
	<?xml version="1.0"?>

I get the error:
	org.xml.sax.SAXParseException: The XML declaration may only appear at the very
beginning of the document.

If I eliminate the xml declaration and start with:
	<xsl:stylesheet version= ... >

Then everything works as expected.